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027
FXUS63 KGRR 311849
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
249 PM EDT Fri May 31 2024

.KEY MESSAGES...

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- Showers/isolated storms Saturday/Sat night

- Next decent chance of rain arrives later Monday

- Strong storms possible Wednesday

- Below normal temperatures for next weekend
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&&

.DISCUSSION...
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Issued at 248 PM EDT Fri May 31 2024

- Showers/Isolated storms Saturday/Sat Night

Latest vis and ir loops show broken cirrus moving across the
state as a weak wave aloft moves east. We won`t see any
precipitation out of this tonight. However, precipitation is in
the forecast Saturday.

Sfc analysis shows a stationary front stretching from northwest WI
southwest to eastern NE. Showers and storms have developed along
the boundary but will remain west of the cwa tonight. That begins
to change Saturday as low pressure over MO moves northeast toward
Lower MI. Forecast soundings show a lot of dry air below 600 mb
except for a narrow wedge near 820 mb. Some of the precipitation
will go toward moistening the column and is the reason the models
have been delaying the arrival of showers. Additionally, CAPE
is meager so this should result in more showers than storms once
the precipitation actually begins which should be after noon and
perhaps as late as mid afternoon.

Model blend has reduced PoPs a bit which makes sense given the
dry air; higher PoPs will be over the southern cwa. The showers
and isolated storms will slowly move east Saturday night, but may
not totally clear the cwa by Sunday morning.

- Next decent chance of rain arrives later Monday

There may be some lingering showers/drizzle very early Sunday
southeast of GRR before the shortwave fully departs, otherwise a dry
day is expected with decreasing clouds.

The next shortwave is shown to arrive from the west for Monday
afternoon or night, bringing a period of higher pops for showers and
possible storms. Only low chance pops look warranted at this time on
Tuesday with mainly isolated pop-up diurnal convection expected in
low shear environment.

- Strong storms possible Wednesday

Pops ramp up again on Wednesday with the approach of the next
shortwave and strong cold front preceding the upper low approaching
from the northwest. Its possible this could be an active severe
weather day depending on degree of instability as deep layer shear
will be on the increase.

- Below normal temperatures for next weekend

Pattern change comes in for the end of next week and next weekend as
large upper low settles into the GrtLks Rgn. Still considerable
spread in eventual position of the upper low and extent of the cool-
down, but H8 temps as low as 2C arrive over the weekend. This would
result in highs only in the 60s along with a daily shower risk.
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&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 112 PM EDT Fri May 31 2024

Very high confidence in VFR weather continuing the next 24 hours,
with cloud bases remaining above 12,000 ft. Showers are expected
to hold off until after 18Z Saturday. Winds will be southerly 5-10
kts, although a bit stronger through 00Z this evening at MKG.

&&

.MARINE...
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Issued at 248 PM EDT Fri May 31 2024

High pressure over the Great Lakes will pose no hazards for small
craft through Sunday night. Once the high moves east and the next
frontal boundary approaches Monday, the pressure gradient will
tighten and winds will increase; a Small Craft Advisory may be
needed Monday.
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&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.

&&

$$

DISCUSSION...Meade/04
AVIATION...Meade
MARINE...04